Q:

Tikz flow chart and beamer

I am creating a beamer presentation. I have following tikz flow chart. The problem is the chart appears to be cluttered and is not accomodated on a single slide.
Here is the code
\documentclass[12pt,a4paper]{beamer}
\usepackage[latin1]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{lmodern}
\usetheme{CambridgeUS}
\usefonttheme{professionalfonts}
\usepackage{tikz}
%\usetheme{AnnArbor}
\author{Dr Vaibhav Banait}
\title{Dysphagia - a serious symptom}
\begin{document}
\begin{frame}
\maketitle
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Dysphagia}
\begin{center}

% Define block styles
\tikzstyle{block} = [rectangle, draw, fill=blue!20, 
    text width=5em, text centered, rounded corners, minimum height=4em]

\begin{tikzpicture}[scale=0.15, node distance=2cm, auto]
    % Place nodes
    \node [] (Dysphagia) {Food sticks in chest after swallowing};
    \node [ below of=Dysphagia] (Esophageal){Esophageal dysphagia};
   \node [ below left  of=Esophageal] (Mechanical) {Solids only };
 \node [ below of = Mechanical](Mechanical1){Mechanical};
    \node [ below left of =Mechanical1](Intermittent){Intermittent};
    \node [ below right of =Mechanical1](Progressive){Progressive};
    \node [ below left of =Progressive](heartburn){Chronic heart burn};
\node [below of=heartburn](peptic){Peptic stricture};
\node[below right of =Progressive](age){Age more than50};
   \node[below of =age](ca){Ca Esophagus }; 
\node [below of =Intermittent](Web){Esophageal web };
\node [below right of=Esophageal](Solidliquids){Solid and liquids=motor };

\node[below right of =Solidliquids](Intermittent1){Intermittent };
\node[below left of =Solidliquids](Progressive1){Progressive};
\node [below of =Intermittent1](chestpain){Chest Pain};
\node [below of =chestpain ](DES){Diffuse esophageal spasm};
\node [below left of = Progressive1](heartburn1){Chronic heart burn};
\node [below of =heartburn1](scleroderma){Scleroderma};
\node [below right of = Progressive1](resp){Respiratory symptoms};
\node[below of =resp](achalasia){achalasia};
    % Draw edges
 \path [draw] (Dysphagia)--(Esophageal);
\path [draw] (Esophageal)--(Mechanical);
\path[draw](Esophageal)--(Solidliquids);
\path[draw](Mechanical)--(Mechanical1);
\path[draw](Mechanical1)--(Progressive);
\path[draw](Mechanical1)--(Intermittent);
\path[draw](Progressive)--(heartburn);
\path[draw](Progressive)--(age);
\path[draw](heartburn)--(peptic);
\path[draw](age)--(ca);
\path[draw](Intermittent)--(Web);
\path[draw](Solidliquids)--(Intermittent1);
\path[draw](Solidliquids)--(Progressive1);
\path[draw](Intermittent1)--(chestpain);
\path[draw](Intermittent1)--(DES);
\path[draw](Progressive1)--(resp);
\path[draw](resp)--(achalasia);
\path[draw](Progressive1)--(heartburn1);
\path[draw](heartburn1)--(scleroderma);
   % \path [line] (Vaibhav) -- (Vibhor);

\end{tikzpicture}

\end{center}

\end{frame}

\end{document}

A:

As John wickerson commented, your flow graph is a tree. forest is a package designed to easily type and draw this kind of trees. But, because this tree is to large to fit inside a frame you can use \resizebox command to adjust it to your slide.
\documentclass[12pt,a4paper]{beamer}
\usepackage[latin1]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{lmodern}
\usetheme{CambridgeUS}
\usefonttheme{professionalfonts}
\usepackage{tikz}
%\usetheme{AnnArbor}
\author{Dr Vaibhav Banait}
\title{Dysphagia - a serious symptom}
\usepackage{forest}
\begin{document}
\begin{frame}
\maketitle
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Dysphagia}

\centering

\resizebox{\textwidth}{.8\textheight}{
\begin{forest}
    [Food sticks in chest after swallowing
        [Esophageal dysphagia
            [Solids only 
           [Mechanical
            [Intermittent
                    [Esophageal web]]
            [Progressive
                [Chronic heart burn
                        [Peptic stricture]]
                    [Age more than50
                       [Ca Esophagus]]]]]
            [Solid and liquids=motor
                [Intermittent 
                    [Chest Pain]
                    [Diffuse esophageal spasm]]
                [Progressive
                    [Respiratory symptoms
                        [achalasia]]
                [Chronic heart burn
                        [Scleroderma]]]]]]
\end{forest}
}
\end{frame}
\end{document}

